1retskroy

Great thread! Had intermittent problems with the unit not lighting off. When I wiggled the four wire connector at the gas valve, it would light. Found this site and re-soldered the connection for the relay on the circuit board. Unit works fine! You need a T-15 Tamper Proof TORX bit ($5.99 @ Harbor Freight Tools) to take the cover off (not a T-10 listed above). This was on a Honeywell SV9500M 2682 gas valve.

Jenn

Hello all, I am facing the same issue, my tech checked it and say that the ignitor is working fine and the computer board is good too, he see the pilot turning on but the gas valve is not opening. After reading all these posts I asked him if there could be a loose connection and if he checked the harness but he is saying that I need to replace the valve and there is no loose connection. He used the voltage meter and he says he is getting 24 volt out of the gas valve... My question is if those soldered connections are bad or my wiring harness is also loose as most of the posters here had found out, would he still get the 24 volt out of the gas valve? or should I try something like you all have tried before spending $200 on a new gas valve and the labor to put it in? Thanks

Jenn

is there is a sensor attached to the ignitor or the gas valve? Now my tech is saying that the sensor might be dirty and that is why it sometimes does not work. He ran into the similar problem somewhere else and cleaned the sensor that had some gas residue and managed to get it fixed? I have asked him to come over but his schedule is pretty much full but he says he will try t be here today.
In the meantime, is it something I could look into? where is this sensor located? any thoughts? It is also very likely that he probably had the same issue with loose connections and while taking things apart, he might have fixed that problem unknowingly... perhaps.

Wuzzat?

He can check connection integrity while current is flowing.
For relay contacts while rated current if flowing, less than 30 mV voltage drop due to contact impedance is good and more than 100 mV is bad.
For a Wirenut carrying 10A, 50 mV is way too much and means it was improperly installed. A good install shows much less drop.

I'd think these numbers would be smaller for a connection that uses tempered spring steel like in your HVAC stuff. The makers of these fasteners may give you pass/fail factory data by their QC people.

Jenn

Thanks Wuzzat.. The tech came in and he tried to clean the sensor next to the ignitor, check few more sensors, confirmed that the gas is actually coming through the gas valve for the small ignitor but there is not gas supply to the bigger pipe going towards the flame.
He does not read these forums so it was hard for me to convince him to open the gas valve beige cover that is attached using couple of either Allen Key or star screws.
His final conclusion is just change the valve, Should I at least try to take the plastic beige piece and see if the problem is same as other fellow posters have described earlier? If I have some photos that would have been a big help. Cheers!

Wuzzat?

Not many people in the US say "cheers".

Ask him how sure he is.
If he is 90% sure it's the valve and the valve costs $X then he should refund you 0.9 of $X if he is wrong!

Ha! Have him put his money where his mouth is.

ghartwell

Boonstra's one hour service just tried to rape me for $910 to replace this valve in my heil furnace. When I phoned Amre supply they quoted me $250 for the valve. I dont mind paying for service or some markup on parts but that is outrageous! Graham Hartwell, Stoney Ontario

Wuzzat?

Seems high.

"The average cost to replace a gas valve in a forces [sic] air furnace can range from $425 to $675."
from
http://www.fastacservice.com/blog/bid/232414/Furnace-Repair-Cost-Find-The-Average-Heating-Repair-Cost

Mine costs $400 years ago but I did all the troubleshooting and left a 20 minute message with his answering machine.
When he showed up at the front door he had the replacement valve in his hand.